Epidemic Intelligence Service National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention Vanderbilt University, Nashville, Tennessee.

2

National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention.

3

Emory University School of Medicine and the VA Medical Center, Atlanta, Georgia.

4

Vanderbilt University, Nashville, Tennessee.

5

Minnesota Department of Health, St Paul.

6

Colorado Department of Public Health and Environment, Denver.

7

New York State Department of Health, Albany.

8

California Department of Public Health, Richmond.

9

Oregon Health Authority, Portland.

10

New Mexico Emerging Infections Program, University of New Mexico, Las Cruces.

11

Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.

12

Connecticut Department of Public Health, Hartford.

Abstract

BACKGROUND:

Invasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of surveillance.

METHODS:

From January 2005 through December 2012, we collected data from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data.

RESULTS:

We identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649-13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136-1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates.

CONCLUSIONS:

The burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.

Incidence and case-fatality rates (CFRs) of invasive group A Streptococcus infections by age group and race in 2005–2012. Race and age group-specific rates of disease were taken from the surveillance areas in continuous use since 2005. Unknown race data were distributed among known values in the surveillance areas.

Distribution of invasive group A streptococcal isolates from Active Bacterial Core surveillance among the 23 most common emm types found during 2005–2012; these included any emm type that comprised >1% of total isolates.